Integrative assessment of multiple pesticides as risk factors for non-Hodgkin’s lymphoma among men
- 1Division of Cancer Epidemiology and Genetics, National Cancer Institute, USA
- 2University of Nebraska Medical Center, Omaha, NE, USA
- 3Kansas University Medical Center, Kansas City, KS, USA
- 4University of Iowa College of Medicine, Iowa City, IA, USA
- Correspondence to: Dr A J De Roos, 1100 Fairview Avenue North, MP-474, PO Box 19024, Seattle, WA 98109, USA;
- Accepted 27 March 2003
Background: An increased rate of non-Hodgkin’s lymphoma (NHL) has been repeatedly observed among farmers, but identification of specific exposures that explain this observation has proven difficult.
Methods: During the 1980s, the National Cancer Institute conducted three case-control studies of NHL in the midwestern United States. These pooled data were used to examine pesticide exposures in farming as risk factors for NHL in men. The large sample size (n = 3417) allowed analysis of 47 pesticides simultaneously, controlling for potential confounding by other pesticides in the model, and adjusting the estimates based on a prespecified variance to make them more stable.
Results: Reported use of several individual pesticides was associated with increased NHL incidence, including organophosphate insecticides coumaphos, diazinon, and fonofos, insecticides chlordane, dieldrin, and copper acetoarsenite, and herbicides atrazine, glyphosate, and sodium chlorate. A subanalysis of these “potentially carcinogenic” pesticides suggested a positive trend of risk with exposure to increasing numbers.
Conclusion: Consideration of multiple exposures is important in accurately estimating specific effects and in evaluating realistic exposure scenarios.